The integrated circuits being used in modern electronic devices, such as computers, are essentially substrates that function like miniature printed circuit boards. Contact pads are deposited on the chips. In order to minimize signal propagation delay and to preserve circuit member real estate, the connection between mating components must be accomplished over as small a path as possible. Therefore, as chip technology advances and the chips increase in size and capability, there is a need for connectors capable of interconnecting the associated high density contact patterns, typically referred to as an area array some of which may have up to 11,500 positions, on a grid as small as one (1.0) millimeter.
A variety of methods have been used to establish the electrical connection. One of these is the interposer-type connector. In this type of connector, it is typical for the electrical connection to occur across spring member contacts contained within a housing. The connector is sandwiched between the mating components. Examples of various interposer-type connectors, and their contacts, are disclosed in U.S. Pat. Nos. 4,969,826 and 5,139,427, assigned to the assignee of the present invention, and U.S. Pat. No. 5,061,192. In the '826 patent a plurality of contact modules, shown with a shunting contact within a two-piece plastic body, are contained within openings in a holder. The '427 patent discloses a connector having contacts positioned between two plastic sheets which are laminated together to make up the body and hold the contacts in place. The '192 patent discloses a connector having a plurality of resilient contact members held in a suspended and spaced orientation by elongated members spanning an opening in a frame.
What is still needed is a connector capable of high density interconnections (1 millimeter or larger grids) that is economical to manufacture, in small lots and in various configurations, having contacts requiring low compressive forces while still insuring reliable and repeatable interconnections with mating circuit members.